ContentPartStream

Model for content part event helpers.

A content part is a single piece of content within a message — text, audio, an image, or a transcript. Use the type-check properties (isText, isMarkdown, isHtml, isAudio, isImage, isTranscript) to determine the content type and handle it accordingly.

Examples¶

message.onContentPartStart((part) => {
  if (part.isMarkdown) {
    part.onChunk((chunk) => {
      process.stdout.write(chunk.data ?? '');
    });
  }
});

message.onContentPartStart((part) => {
  if (part.isText) {
    part.onChunk((chunk) => showPlainText(chunk.data ?? ''));
  } else if (part.isMarkdown) {
    part.onChunk((chunk) => renderMarkdown(chunk.data ?? ''));
  } else if (part.isHtml) {
    part.onChunk((chunk) => renderHtml(chunk.data ?? ''));
  } else if (part.isAudio) {
    part.onChunk((chunk) => audioPlayer.enqueue(chunk.data ?? ''));
  } else if (part.isImage) {
    part.onChunk((chunk) => imageBuffer.append(chunk.data ?? ''));
  } else if (part.isTranscript) {
    part.onChunk((chunk) => showTranscript(chunk.data ?? ''));
  }
});

message.onContentPartStart((part) => {
  part.onCompleted((completed) => {
    console.log(`Full text: ${completed.data}`);

    // Access citations — each has offset, length, and sources
    for (const citation of completed.citations) {
      const citedText = completed.data.substring(
        citation.offset,
        citation.offset + citation.length
      );
      console.log(`"${citedText}" cited from:`, citation.sources);
    }
  });
});

message.onContentPartCompleted((completed) => {
  console.log(`[${completed.mimeType}] ${completed.data}`);
});

Properties¶

Property	Modifier	Type	Description
`contentPartId`	`readonly`	`string`	Unique identifier for this content part
`ended`	`readonly`	`boolean`	Whether this content part has ended
`isAudio`	`readonly`	`boolean`	Whether this content part is audio content
`isHtml`	`readonly`	`boolean`	Whether this content part is HTML. Matches `text/html`.
`isImage`	`readonly`	`boolean`	Whether this content part is an image
`isMarkdown`	`readonly`	`boolean`	Whether this content part is markdown. Matches `text/markdown`.
`isText`	`readonly`	`boolean`	Whether this content part is plain text. Matches `text/plain`.
`isTranscript`	`readonly`	`boolean`	Whether this content part is a transcript (from speech-to-text)
`mimeType`	`readonly`	`undefined` \| `string`	The MIME type of this content part, or undefined if start event not yet received

Methods¶

onChunk()¶

onChunk(cb: (chunk: ContentPartChunkEvent) => void): () => void

Registers a handler for content part chunks

Chunks are the fundamental unit of streaming data. Each chunk contains a piece of the content (text, audio data, etc.).

Parameters¶

Parameter	Type	Description
`cb`	(`chunk`: `ContentPartChunkEvent`) => `void`	Callback receiving each chunk

Returns¶

Cleanup function to remove the handler

(): void

Returns¶

void

Example¶

part.onChunk((chunk) => {
  process.stdout.write(chunk.data ?? '');
});

onCompleted()¶

onCompleted(cb: (completedContentPart: CompletedContentPart) => void): void

Registers a handler called when this content part finishes

The handler receives the aggregated content part data including all buffered text, citations, and any citation errors.

Parameters¶

Parameter	Type	Description
`cb`	(`completedContentPart`: `CompletedContentPart`) => `void`	Callback receiving the completed content part data

Returns¶

void

Example¶

part.onCompleted((completed) => {
  console.log(`Content type: ${completed.mimeType}`);
  console.log(`Full text: ${completed.data}`);

  // Citations provide offset/length into the text and source references
  for (const citation of completed.citations) {
    const citedText = completed.data.substring(
      citation.offset,
      citation.offset + citation.length
    );
    console.log(`"${citedText}" — sources:`, citation.sources);
  }

  // Citation errors indicate malformed citation ranges
  if (completed.citationErrors.length > 0) {
    console.warn('Citation errors:', completed.citationErrors);
  }
});

onContentPartEnd()¶

onContentPartEnd(cb: (endContentPart: ContentPartEndEvent) => void): () => void

Registers a handler for content part end events

Parameters¶

Parameter	Type	Description
`cb`	(`endContentPart`: `ContentPartEndEvent`) => `void`	Callback receiving the end event

Returns¶

Cleanup function to remove the handler

(): void

Returns¶

void

Example¶

part.onContentPartEnd((endEvent) => {
  console.log('Content part finished');
});

onErrorEnd()¶

onErrorEnd(cb: (error: { errorId: string; } & ErrorEndEvent) => void): () => void

Registers a handler for error end events

Parameters¶

Parameter	Type	Description
`cb`	(`error`: { `errorId`: `string`; } & `ErrorEndEvent`) => `void`	Callback receiving the error end event

Returns¶

Cleanup function to remove the handler

(): void

Returns¶

void

onErrorStart()¶

onErrorStart(cb: (error: { errorId: string; } & ErrorStartEvent) => void): () => void

Registers a handler for error start events

Parameters¶

Parameter	Type	Description
`cb`	(`error`: { `errorId`: `string`; } & `ErrorStartEvent`) => `void`	Callback receiving the error event

Returns¶

Cleanup function to remove the handler

(): void

Returns¶

void

Example¶

part.onErrorStart((error) => {
  console.error(`Content part error: ${error.message}`);
});

sendChunk()¶

sendChunk(chunk: ContentPartChunkEvent): void

Sends a content part chunk

Parameters¶

Parameter	Type	Description
`chunk`	`ContentPartChunkEvent`	Chunk data to send

Returns¶

void

Example¶

part.sendChunk({ data: 'Hello ' });
part.sendChunk({ data: 'world!' });

sendContentPartEnd()¶

sendContentPartEnd(endContentPart?: ContentPartEndEvent): void

Ends the content part stream

Parameters¶

Parameter	Type	Description
`endContentPart?`	`ContentPartEndEvent`	Optional end event data

Returns¶

void

Example¶

part.sendContentPartEnd();